The 1999 GMC Yukon is available as a 4-door, 5-seat sport utility. Starting at $30,139, the 1999 GMC Yukon SLE 4x2 is powered by a 5.7L, 8-cylinder engine mated to an automatic transmission that returns an EPA estimated 14-mpg in the city and 18-mpg on the highway. The top of the line 1999 GMC Yukon SLT GM BuyPower 4x4, priced at $33,139, is powered by a 5.7L, 8-cylinder engine mated to an automatic transmission that returns an EPA estimated 12-mpg in the city and 16-mpg on the highway.